Searching recorded video can be an extremely time consuming and labor intensive process. Video surveillance systems normally include a recorder for recording the video captured by the surveillance cameras. Initially, videocassette recorders were used for recording this data; however, the tapes could only be searched by having personnel review the tapes to find the portion of interest. The development of digital video recorders improved the searching process with the use of algorithms to search for specific items, such as when an item has disappeared from the area being viewed by the video camera. However, the ability to quickly and easily find a specific video clip of a specified object or person has not significantly improved; the process still requires personnel to review the video as with VCR tapes.
Video analytics is quickly gaining attention within the video security industry, and systems and components that use rather advanced techniques for extracting high-level information from a digital video stream are starting to be deployed. Color similarity matching is an especially difficult task for video analytics. It is difficult to find a robust way of matching colors. One problem involves the way colors are perceived by the human vision system. An investigator may want to locate a suspect wearing clothes of a specified color. For example, a task could be given to find all pedestrians wearing a dark red shirt with dark blue jeans. Currently, all investigations involve individuals (hundreds of individuals in some cases such as the London bombings of 2005) manually searching through hours of video in real-time or at best fast-forward. Researchers have tried many color models to search for perceived color. Some of the color models include color histograms, dominant colors, color layout, color structure, etc. None of these color models have proven to be accurate in identifying a specified color object or person all the time. For this reason, most video object identification methods ignore color and work with gray scale images.